If 2-3 drops of phenolphthalein are added to basic solutions?then what change will be observed
Answers
Answered by
1
The phenolphthalein indicator has two different structures based on whether it is in an alkali (pink) or acid (colorless) solution. Both structures absorb light in the ultra-violet region, a region not accessible for the human eye. However, the pink form also absorbs in the visible light spectrum.
The reason for the visible light absorption is the structure of the pink form of the phenolphthalein indicator. Due to ionization, the electrons in the molecule are more delocalized than in the colorless form. Briefly, delocalization is when electrons in a molecule are not associated with a single atom, and instead are spread over more than one atom.
An increase in delocalization shifts the energy gap between molecular orbitals. Less energy is needed for an electron to make the jump into a higher orbital. The absorption of energy is in in the green region, 553 nanometers, of the light spectrum.
The human eye perceives a pink hue in the solution. The stronger the alkaline solution is, the more the phenolphthalein indicator changes and the darker the pink hue will be.
The reason for the visible light absorption is the structure of the pink form of the phenolphthalein indicator. Due to ionization, the electrons in the molecule are more delocalized than in the colorless form. Briefly, delocalization is when electrons in a molecule are not associated with a single atom, and instead are spread over more than one atom.
An increase in delocalization shifts the energy gap between molecular orbitals. Less energy is needed for an electron to make the jump into a higher orbital. The absorption of energy is in in the green region, 553 nanometers, of the light spectrum.
The human eye perceives a pink hue in the solution. The stronger the alkaline solution is, the more the phenolphthalein indicator changes and the darker the pink hue will be.
Similar questions